Completion of a chemical synthesis of the potent cytotoxic antibiotic verrucarin A is projected by combination of synthetic verrucarol with the dicarboxylic acid which constitutes the acyclic segment of this macrolide. Ongoing studies directed towards a total synthesis of the ionophoric antibiotic boromycin will focus on assembling "northern" and "southern" halves of this macrolide around the borate core. This strategy will be extended to an approach to the related boron-containing antibiotic aplasmomycin. A plan for the synthesis of latrunculin, an unusual cysteine-containing macrolide from a marine source and a potent cholinesterase inhibitor, is presented in which stereochemistry is established by chiral transfer from the amino acid. Finally, a route to avermectin B1a (AVM), a broad-spectrum anthelmintic from a Streptomyces organism, is set forth using a convergence fo four independently constructed segments to establish the complete structural array of this macrolide.